JP4398463B2 - Method, system, and program for incremental virtual copy - Google Patents

Abstract

Disclosed is a technique for reducing an amount of data transferred. A first indicator is maintained for each source block of data to indicate whether the source block of data has been updated in source storage since the source block of data was last transferred to target storage. A second indicator is maintained for each target block of data in target storage to indicate whether the target block of data has been updated in target storage since the target block of data was overwritten by a corresponding source block of data. When transferring data from the source storage to the target storage, each source block of data for which a first indicator has been set to indicate that the source block of data has been updated is transferred and each source block of data that corresponds to a target block of data for which a second indicator has been set to indicate that the target block of data has been updated is transferred.

Description

  The present invention is directed to incremental virtual copying.

  Computing systems often process one or more host computers (“hosts”) for processing data and running application programs, direct access storage devices (DASD) for storing data, And a storage controller for controlling data transfer between the host and the DASD. A storage controller, also called a control unit or storage director, manages access to storage space consisting of a number of hard disk drives connected in a loop architecture, and in other cases is called a direct access storage device (DASD) . The host can communicate input / output (I / O) requests for the storage space through the storage controller.

  In many systems, data on one storage device, such as DASD, can be copied to the same or another storage device so that access to the data volume is provided from two different devices. Point-in-time copying is a physical copy of all data from a source volume to a target volume, so that the target volume has a copy of the data at the point-in-time. Including. Point-in-time copying can effectively delay the physical copying operation by simply making a logical copy of the data and then only copying over the data when needed. When this logical copy operation is performed, the time during which the target volume and the source volume are inaccessible can be minimized.

  Many direct access storage device (DASD) subsystems can perform “instant virtual copy” operations, also called “fast replication features”. An immediate virtual copy operation is performed by modifying metadata or pointers, such as an association table, and treating the source data object as both an original and a copy. In response to a host copy request, the storage subsystem immediately reports the creation of a copy without creating a physical copy of any data. Only a “virtual” copy is created and the absence of an additional physical copy is completely unknown to the host.

  If the storage system later receives an original or copy update, the update is stored separately and only cross-referenced to the updated data object. At this point, the differentiation of the original data object and the copy data object begins. The first advantage is that immediate virtual copy occurs almost instantaneously and completes much faster than normal physical copy operations. This frees the host and storage subsystem and allows other tasks to be performed. The host or storage subsystem can even make an actual physical copy of the original data object, either in background processing or on another occasion.

  One such immediate virtual copy operation is known as a FlashCopy ™ operation. The FlashCopy ™ operation involves establishing a logical point-in-time relationship between a source volume and a target volume on the same or different devices. The FlashCopy ™ operation ensures that the track resides on the source disk until the position of the track in the FlashCopy ™ association on the target disk is fixed. A relationship table is used to maintain information about all existing FlashCopy ™ relationships in the subsystem. In the FlashCopy ™ relationship establishment phase, an entry is recorded in the source and target relationship table for the sources and targets that participate in the established FlashCopy ™. Each appended entry maintains all the required information regarding the FlashCopy ™ relevance. Both entries for relevance are removed from the relevancy table when all FlashCopy ™ tracks from the source area are physically copied to the target area or a withdrawal command is received. . In some cases, the relationship persists even if all tracks are copied from the source area to the target area.

  The target association table further includes a bitmap that identifies which tracks included in the FlashCopy ™ association have not yet been copied and are therefore protected tracks. Each track in the target device is represented by one bit in the bitmap. The target bit is set when the corresponding track is established as a FlashCopy (TM) related target track. The target bit is reset when the corresponding track is copied from the source location and destaged to the target device for a write or background copy task on the source or target device.

  In the prior art, as part of establishing a logical point-in-time relationship during FlashCopy ™ operation, all tracks in the source cache included in the FlashCopy ™ relationship are physically A new source volume, eg source DASD, must be destaged and all tracks in the target cache contained in FlashCopy ™ must be discarded.

  Once the logical association is established, the host can then immediately access the data on the source and target volumes, which can be copied as part of the background operation. A read on a track when the track is a target in FlashCopy ™ relevance and not in the cache triggers a stage intercept, the source track has not yet been copied and the track is accessed from the target cache The source track corresponding to the requested target track is staged in the target cache. This ensures that the target has a copy from the source that existed at the point of time of the FlashCopy ™ operation. In addition, any write to a track on the source device that has not been copied over triggers a destage intercept, causing the track on the source device to be copied to the target device.

  Instant virtual copy technology has been developed to quickly (at least partially) create duplicate copies of data without interrupting or slowing down foreground processing. Immediate virtual copy technology such as FlashCopy ™ operation provides a point-in-time copy tool. The immediate virtual copy technology can be used for various applications including, for example, data backup, data migration, data mining, testing, and the like. For example, immediate virtual copy technology can be used to create a physical “backup” copy of the source data to aid in disaster recovery.

  Although the immediate virtual copy technology is useful for copying a large amount of data, the conventional immediate virtual copy technology can also be improved. In particular, there is a need in the art for improved instant virtual copy technology that avoids physically copying large amounts of data.

  In a first aspect, the invention provides for each source data block to indicate whether the source data block has been updated in the source store since the last time the source data block was transferred to the target store. Maintaining a first indicator for the block and indicating whether the target data block has been updated in the target store since the target data block was overwritten by the corresponding source data block; Maintaining a second indicator for each target data block in the target store and indicating that the source data block has been updated when transferring data from the source store to the target store Each saw with the first indicator set Transfer each source data block corresponding to the target data block with the second indicator set to transfer the data block and to indicate that the target data block has been updated A method for reducing the amount of data transferred.

  The method further comprises maintaining a third indicator for each target data block indicating whether the corresponding source data block or target data block should be retrieved for stage operation. It is preferable to include.

  The method preferably further comprises the step of updating a third indicator for the target data block when the source data block is copied to the target store.

  The method is based on receiving an incremental virtual copy operation, a first indicator for a source data block and a second indicator for a target data block corresponding to the source data block, Updating a third indicator for each target data block, wherein transferring data from the source store to the target store is transferred from the source data block to the target store. Preferably, it includes transferring each source data block, where the third indicator indicates that it should be done.

  After establishing the incremental virtual copy relevance, the method sets each source data block corresponding to the target data block to be retrieved from the source store for stage operation. Preferably, the method further comprises updating a third indicator for the target data block.

  In this method, after data is transferred from the source storage to the target storage, the source data block is not updated in the source storage since the last time the source data block was transferred to the target storage. Preferably, the method further includes updating the first indicator for each source block.

  The method does not update the target data block in the target store after the last transfer of the source data block to the target store after transferring data from the source store to the target store. Preferably, the method further includes updating a second indicator for each target data block.

  Each source data block and each target data block preferably includes a volume of tracks.

  Each source data block and each target data block preferably includes a sector of a volume.

  The method further comprises the step of forming an incremental virtual copy relationship between the source portion of the data and the target portion of the data by performing an incremental virtual copy operation between the source portion of the data and the target portion of the data. Where, in an incremental virtual copy relationship, a first indicator for each source data block in the source portion of data and a second indicator for each target data block in the target portion of data are Maintained.

  The method updates the first indicator for each source data block to indicate that the source data block has not been updated, and indicates that the target data block has not been updated. As shown, for each target data block, updating the second indicator for each target data block and indicating that the source data block needs to be transferred to the target store Preferably updating the third indicator of.

  The method may further include updating a first indicator for the source data block to indicate that the source data block has been updated when the source data block is updated. preferable.

  The method may further include updating a second indicator for the target data block to indicate that the target data block has been updated when the target data block is updated. preferable.

  Similarly, a first indicator for each source data block that indicates whether the source data block has been updated in the source store since the last time the source data block was transferred to the target store And each target in the target store that indicates whether the target data block has been updated in the target store since the target data block was overwritten by the corresponding source data block. Maintaining a second indicator for the data block, and when transferring data from the source store to the target store, the first indicator is set to indicate whether the source data block has been updated. Each source data block And transferring each source data block corresponding to the target data block with a second indicator set to indicate whether the target data block has been updated. It is also possible to provide a product for reducing the amount of data transferred on which the operation takes place.

  The product further comprises maintaining a third indicator for each target data block indicating whether the corresponding source data block or target data block should be retrieved for stage operation. It is preferable to perform the operation including.

  The product preferably includes updating a third indicator for the target data block when the source data block is copied to the target store.

  The product includes a step of receiving an incremental virtual copy operation and a first indicator for a source data block and a second indicator for a target data block corresponding to the source data block, Updating a third indicator for the target data block, wherein transferring the data from the source store to the target store is such that the source data block is the target store. Transferring each source data block, the third indicator indicating that it should be transferred to

  After establishing the incremental virtual copy relevance, the product will indicate that the source data block corresponding to the target data block should be retrieved from the source store for stage operation. Preferably, the method includes updating a third indicator for the target data block.

  In this product, after transferring data from the source storage to the target storage, the source data block was not updated in the source storage since the last time the source data block was transferred to the target storage As indicated, it preferably includes the step of updating a first indicator for each source block.

  In this product, after transferring data from the source storage to the target storage, the target data block was not updated in the target storage since the last time the target data block was transferred to the target storage As indicated, it preferably includes the step of updating a second indicator for each target data block.

  Each source data block and each target data block preferably includes a volume of tracks.

  Each source data block and each target data block preferably includes a sector of a volume.

  The product includes the step of forming an incremental virtual copy relationship between the source portion of the data and the target portion of the data by performing an incremental virtual copy operation between the source portion of the data and the target portion of the data. Preferably, in an incremental virtual copy relationship, a first indicator for each source data block in the source portion of data and a second for each target data block in the target portion of data An indicator is maintained.

  The product updates the first indicator for each source data block to indicate that the source data block has not been updated and indicates that the target data block has not been updated. As shown, for each target data block, updating the second indicator for each target data block and indicating that the source data block needs to be transferred to the target store Preferably updating the third indicator of.

  The product may further include updating a first indicator for the source data block to indicate that the source data block has been updated when the source data block is updated. preferable.

  The product may further include updating a second indicator for the target data block to indicate that the target data block has been updated when the target data block is updated. preferable.

  In a second aspect, the present invention provides each source data block indicating whether the source data block has been updated in the source store since the last time the source data block was transferred to the target store. Means for maintaining a first indicator for the block and whether the target data block has been updated in the target store since the target data block was overwritten by the corresponding source data block; Means for maintaining a second indicator for each target data block in the target store, and whether the source data block was updated when transferring data from the source store to the target store The first indicator was set to indicate Means for transferring each source data block and each source data block corresponding to the target data block with a second indicator set to indicate whether the target data block has been updated And a system for reducing the amount of data transferred, including means for transferring blocks.

  The system includes means for maintaining a third indicator for each target data block that indicates whether the corresponding source data block or target data block should be retrieved for stage operation. It is preferable to contain.

  The system preferably includes means for updating a third indicator for the target data block when the source data block is copied to the target store.

  The system is configured to receive each incremental virtual copy operation, and based on a first indicator for the source data block and a second indicator for the target data block corresponding to the source data block, Updating a third indicator for the target data block, wherein transferring the data from the source store to the target store is such that the source data block is the target store. Preferably, it includes means for transferring each source data block, wherein the third indicator indicates that it should be transferred to.

  After establishing the incremental virtual copy relevance, the system will indicate that the source data block corresponding to the target data block should be retrieved from the source store for stage operation. Preferably, means are included for updating a third indicator for the target data block.

  In this system, after transferring data from the source storage to the target storage, the source data block was not updated in the source storage since the last time the source data block was transferred to the target storage As indicated, it preferably includes means for updating the first indicator for each source data block.

  The system did not update the target data block in the target store after the last time the source data block was transferred to the target store after transferring data from the source store to the target store As indicated, it preferably includes means for updating the second indicator for each target data block.

  Each source data block and each target data block preferably includes a volume of tracks.

  Each source data block and each target data block preferably includes a sector of a volume.

  The product provides a means for creating an incremental virtual copy relationship between a data source portion and a data target portion by performing an incremental virtual copy operation between the data source portion and the data target portion. Where, in an incremental virtual copy relationship, a first indicator for each source data block in the source portion of data and a second indicator for each target data block in the target portion of data Is preferably maintained.

  The system has means for updating the first indicator for each source data block and the target data block has not been updated to indicate that the source data block has not been updated. Means for updating the second indicator for each target data block and each target data block to indicate that the source data block needs to be transferred to the target store. And means for updating a third indicator for the data block.

  The system may include means for updating a first indicator for the source data block to indicate that the source data block has been updated when the source data block is updated. preferable.

  The system preferably includes means for updating a second indicator for the target data block to indicate that the target data block has been updated when the target data block is updated.

  In a third aspect, the present invention includes a computer program code for causing a method step according to the first aspect to be executed when read into a computer system and executed on the computer system.・ Provide programs. Preferred features of the computer program include computer program code corresponding to the preferred method steps of the first aspect.

  Therefore, it is preferable to provide a method, system and program for reducing the amount of data transferred. A first indicator for each source data block is maintained that indicates whether the source data block has been updated in the source store since the last time the source data block was transferred to the target store. The A first for each target data block in the target store that indicates whether the target data block has been updated in the target store since the target data block was overwritten by the corresponding source data block. Two indicators are maintained. When transferring data from the source store to the target store, each source data block with a first indicator set to indicate that the source data block has been updated is transferred and the target data Each source data block corresponding to the target data block is transferred with the second indicator set to indicate that the block has been updated.

  The described implementation of the invention provides a method, system, and program for creating incremental virtual copies.

  Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

  In the following description, reference is made to the accompanying drawings that form a part hereof and in which are shown several embodiments of the invention. It is understood that other implementations can be used and structural and operational changes can be made without departing from the scope of the invention.

  The implementation of the present invention provides an incremental virtual copy operation that enhances the functionality of an immediate virtual copy operation. When using an incremental virtual copy operation, only the data blocks that have been updated in the source and target volumes since the last immediate virtual copy operation from the source volume to the target volume are copied. Incremental virtual copy operations reduce the time to create a physical copy of the source volume and minimize the impact on other applications (for example, using bandwidth for physical storage to destage data). Minimize, which allows a lot of bandwidth for reading from the physical store).

  1 and 2 illustrate in a block diagram a computing environment in accordance with a particular implementation of the present invention. The storage controller 100 sends input / output (I / O) requests to the hosts 140a, b,. . . l (where a, b and l can be any integer value) and volumes (eg, logical unit numbers, logical devices, etc.) 122a, b. . . n and 132a, b. . . Directed toward storage devices 120, 130 configured to have each of m, where m and n may be different integer values or may be the same integer value. In particular implementations, the size of the target store 130 can be greater than or equal to the source store 120.

  The source storage 120 may be divided into one or more volumes 122a, b. . . This storage block 150 is further divided into storage sub-blocks (150a-150p, where a and p can be any integer value) including sub-blocks of data. A volume can be any logical or physical element of the storage. In a particular implementation, the data block is the content of the track and the data sub-block is the content of the sector of the track.

  The target storage unit 130 includes volumes 122a, b. . . Maintain a copy of all or a subset of n. Furthermore, the target storage unit 130 can be modified by the host 140, for example. The target storage unit 130 can be divided into one or more volumes 132a, b. . . storage block 150 is further subdivided into storage sub-blocks (150a-150p, where a and p can be any integer value) including sub-blocks of data. A volume can be any logical or physical element of the storage. In a particular implementation, the data block is a track and the data sub-block is a sector of the track.

  For simplicity of reference, the terms track and sector are used herein as examples of data blocks and data sub-blocks, but the use of these terms makes track and sector implementation of the present invention. It is not intended to be limited to. The implementation of the present invention is also applicable to any type of storage, or storage block or data block divided in any way. Furthermore, although the implementation of the present invention refers to data blocks, alternative implementations of the present invention are also applicable to data sub-blocks.

  The storage controller 100 includes a source cache 124 where updates to tracks in the source store 120 are written until written to the source store 120 (ie, the track is destaged to the physical store). Maintained. The storage controller 100 includes a target cache 134 where updates to tracks in the target store 130 are written until the target store 130 is written (ie, the track is destaged to the physical store). Maintained. Source cache 124 and target cache 134 may include different sections of separate or the same storage device. Source cache 124 and target cache 134 are connected to hosts 140a, b,. . . l, read data and write data transmitted between the source storage unit 120 and the target storage unit 130 are used for buffering. In addition, caches 124 and 134 are referred to as source and target caches and hold source or target data blocks that are in a point-in-time copy relationship, but these caches 124. And 134 can simultaneously store source and target data blocks that are in different point-in-time copy relationships.

  In addition, the storage controller 100 includes a non-volatile cache 118. The non-volatile cache 118 may be a battery-backed volatile memory, for example, to maintain a non-volatile copy of the data update.

  The storage controller 100 further includes a system memory 110 that can be implemented in volatile and / or non-volatile devices. The system memory 110 includes a read process 112 for reading data, a write process 114 for writing data, and an incremental virtual copy process 116. The read process 112 is executed in the system memory 110 and reads data from the storage unit 120 to the cache 124 and from the storage unit 130 to the cache 134. The write process 114 is executed in the system memory 110 and writes data from the cache 124 to the storage unit 120 and from the cache 134 to the storage unit 130. The incremental virtual copy process 116 is executed in the system memory 110 and executes an incremental virtual copy operation for transferring data from the source storage unit 120 to the target storage unit 130. In a particular implementation of the invention, there are a number of incremental virtual copy processes. In certain implementations of the invention, instead of or in addition to being executed at the storage controller 100, the incremental virtual copy process may be executed at another storage controller connected to the storage controller 100. The system memory 110 may be in a storage device that is separate from the caches 124 and 134 or may share the storage device with one or both of the caches 124 and 134.

  For ease of reference, the implementation of the present invention is also applicable to data transfer between any two storage media, referred to herein as source storage and target storage. For example, as shown in FIG. 1, a particular implementation of the present invention can be used with two storage media located in a single storage controller. Further, alternative specific implementations of the present invention can be used with two storage media located at different storage controllers, different physical sites, and the like. In order to simplify the reference, a data block in the source storage unit is called a “source data block”, and a data block in the target storage unit is called a “target data block”.

  In certain implementations, removable storage can be used (instead of or in addition to target storage 130) to maintain a copy of all or a subset of source storage 120, and implementations of the invention , Transfer the data to the removable storage instead of the target storage. The removable storage can reside in the storage controller 100.

  The storage controller 100 further includes a processor complex (not shown) and can include any storage controller or server known in the art, such as Enterprise Storage Server 7 (ESS ™), 39907 Storage Controller, etc. . Hosts 140a, b. . . l can include any computing device known in the art, such as a server, mainframe, workstation, personal computer, handheld computer, laptop telephony device, network appliance, and the like. Storage controller 100 and host systems 140a, b. . . 1 communicates over a network 190 that may include a storage area network (SAN), a local area network (LAN), a wide area network (WAN), the Internet, an intranet, and the like. Each of the source storage unit 120 and the target storage unit 130 may include an array of storage devices such as a direct access storage device (DASD), a simple disk bundle (JBOD), a new magnetic disk control mechanism array (RAID), and a virtualization device. .

  In addition, although FIG. 1 shows a single storage controller, those skilled in the art will recognize many via a network (eg, a local area network (LAN), a wide area network (WAN), the Internet, etc.). It will be appreciated that multiple storage controllers can be connected and that one or more of the multiple storage controllers can implement the present invention.

When the host 140 wishes to update a data block in the source store 120, the host 140 writes data to the store block in the source cache 124. A write operation synchronously modifies the storage block in the source cache 124 (ie, the write host 140 waits for the operation to complete), and then in background processing, the contents of the source cache 124 are transferred to the source store 120. Is written to. A write operation can update data, write new data, or write the same data again. Writing data in the source cache 124 to the source storage unit 120 is called a destage operation. Copying all or part of a data block from the source store 120 to the source cache 124 is a stage operation. Similarly, data can be staged and destaged between the target store 130 and the target cache 134. In addition, data can be staged from the source storage 120 to the target cache 134.

  FIG. 3 illustrates various structures 200, 210, and 220 according to certain implementations of the invention. The non-volatile cache 118 includes a target copy structure 200. The target copy structure 200 can be used to determine whether data is retrieved from the source store 120 to the cache 124 or from the target store 130 to the cache 134 (ie, for stage operations). Furthermore, the target copy structure 200 can be used to determine which data blocks in the source storage 120 are copied to the target storage 130. The target copy structure 200 includes, for example, an indicator (eg, 1 bit) for each data block in the volume. When the indicator is set to a first value (e.g., 1), the setting indicates that the data block should be retrieved from the source store 120 for stage operation, or an incremental virtual copy Indicates that the data block should be copied to the target store 130 for operation. If the indicator is set to a second value (eg, zero), the setting indicates that the data block should be retrieved from the target store 130 for stage operation, or an incremental virtual copy. Indicates that the data block should be copied from the source store 120 to the target store 130 for operation.

  A source change record structure 210 is used to monitor the update of data blocks in the portion of data in the source store 120 where the incremental virtual copy relevance has been established. The source change recording structure 210 includes an indicator (eg, 1 bit) for each data block in the source store 120 that is part of the incremental virtual copy relationship. If the indicator is set to a first value (eg, 1), the setting indicates that the data block has been updated since the last incremental virtual copy operation. If the indicator is set to a second value (eg, zero), the setting indicates that the data block has not been updated since the last incremental virtual copy operation.

  After the incremental virtual copy relevance is established, the target change recording structure 220 is used to monitor updates of data blocks in the target store 130. The target change recording structure 220 includes an indicator (eg, a bit) for each data block in the target store 130 that is part of the incremental virtual copy relevance. If the indicator is set to a first value (eg, 1), the setting indicates that the data block has been updated since the last incremental virtual copy operation. If the indicator is set to a second value (eg, zero), the setting indicates that the data block has not been updated since the last incremental virtual copy operation.

  In a particular implementation of the invention, each structure 200, 210, and 220 includes a bitmap and each indicator includes a bit. In each structure 200, 210, and 220, the nth indicator corresponds to the nth data block (eg, the first indicator in each structure 200, 210, and 220 is Corresponding to the first data block). Although structures 200, 210, and 220 have been shown as three separate structures, these structures may be combined in any form without departing from the scope of the present invention. In a particular implementation of the invention, there is a copy of each structure for each volume. In certain alternative implementations of the invention, there is a single copy of each structure for every volume.

  FIG. 4 illustrates the logic implemented in the incremental virtual copy process 116 for updating a structure in accordance with a particular implementation of the present invention. At block 300, control begins with the initial establishment of an incremental virtual copy relationship. When an incremental virtual copy operation is performed between corresponding portions of data, one or more portions of data in the source store 120 (eg, source volume) and corresponding data in the target store 130 An incremental virtual copy relationship is formed with a portion (eg, target volume). The first incremental virtual copy operation can, for example, copy one or more source volumes to corresponding target volumes. However, the next copy creates an incremental copy and can avoid recopying any part of the source volume that has not changed since the last immediate virtual copy operation.

  At block 310, the incremental virtual copy process 116 updates the indicator in the target copy structure 200, and all data blocks corresponding to the indicator should be retrieved from the source store for stage operation. And that all data blocks should be copied from the source store to the target store for an incremental virtual or physical copy operation. In a particular implementation of the invention, the indicator in the target copy structure 200 is set to 1.

  In block 320, the incremental virtual copy process 116 updates the indicator in the source change recording structure 210 to indicate that the source data block corresponding to the indicator has not been updated since the last incremental virtual copy operation. In a particular implementation of the invention, all indicators in the source change recording structure 210 are set to zero. In block 330, the incremental virtual copy process 116 updates the indicator in the target change recording structure 220 to indicate that the target data block corresponding to the indicator has not been updated since the last incremental virtual copy operation. In a particular implementation of the present invention, all indicators in the target change recording structure 220 are set to zero.

  FIG. 5 illustrates the logic implemented in the incremental virtual copy process 116 for performing an incremental virtual copy operation in accordance with a particular implementation of the present invention. At block 400, control begins with an incremental virtual copy process 116 that receives an incremental virtual copy operation. An incremental virtual copy operation can also be performed by the host 140. Although not illustrated in the flow of FIG. 5, one or more data blocks in the source store 120 and / or the target store 130 are received, for example, by a user at the host 140, prior to receiving an incremental virtual copy operation. Can be updated.

  At block 410, the incremental virtual copy process 116 updates the indicator in the target copy structure 200 with the indicators in the source change recording structure 210 and the target change recording structure 220. In a particular implementation of the present invention, the source change recording structure 210 is merged with the target change recording structure 220 using an “OR” operation, and the result of the “OR” operation is sent to the target copy structure 200 as “logic”. It is “summed”.

  After the target copy structure 200 is updated at block 420, the incremental virtual copy process 116 updates the indicator in the source change recording structure 210 so that the source data block has been updated since the last incremental virtual copy operation. Indicates that it was not updated. In a particular implementation of the present invention, all indicators in the source change recording structure 210 are set to zero. In block 430, the incremental virtual copy process 116 updates the indicator in the target change recording structure 220 to indicate that the target data block has not been updated since the last incremental virtual copy operation. In a particular implementation of the invention, all indicators in the target change recording structure 220 are set to zero.

  FIG. 6 illustrates the logic performed in the write process 114 for processing write operations in accordance with a particular implementation of the present invention. In block 500, control begins with a write process 114 that receives a data block write request. At block 520, the write process 114 determines whether the data block is in an incremental virtual copy relationship. If the data block is in an incremental virtual copy relationship, processing continues at block 530, otherwise processing continues at block 560. In block 530, the write process 114 determines whether the data block is in the target store 130. If the data block is in the target store 130, processing continues at block 540, otherwise processing continues at block 550.

  At block 540, the indicator for the data block in the target change recording structure 220 is updated to indicate that the target data block has changed since the last incremental virtual copy operation. In a particular implementation of the present invention, the indicator in the target change recording structure 220 is set to 1. At block 550, the indicator for the data block in the source change recording structure 210 is updated to indicate that the source data block has changed since the last incremental virtual copy operation. In a particular implementation of the present invention, the indicator in the source change recording structure 210 is set to 1. In block 560, the write operation is performed by the write process 114.

  FIG. 7 illustrates the logic implemented in the read process 112 for processing read operations in accordance with a particular implementation of the present invention. In block 600, control begins with receipt of a data block read request. At block 620, the read process 112 determines whether the data block is a target that is in incremental virtual copy relevance. If the data block is a target that is in an incremental virtual copy relationship, processing continues to block 630; otherwise, processing continues to block 660. At block 630, the read process determines whether an indicator for the data block is set in the target copy structure and indicates that the data is read from the source store 120. If the indicator for the data block is set in the target copy structure, processing continues at block 640, otherwise processing continues at block 650.

  At block 640, the read process 112 reads (ie, stages) the data block from the source store 120. At block 650, the read process 112 reads (ie, stages) the data block from the target store 130. At block 660, the read process 112 performs a normal read of the data block.

  FIG. 8 illustrates a background copy process according to a particular implementation of the present invention. In block 700, control begins with a determination of whether it is time to copy the data block. At block 710, it is determined whether an indicator in the target copy structure for the data block indicates that the data block has not been copied. If it indicates that the data block has not been copied, processing continues at block 730; otherwise, processing continues at block 720. At block 720, the next data block can be processed, or the logic ends if no other data block is processed.

  At block 730, the data block is read according to the logic of FIG. At block 740, the data block is destaged to the target store 130. At block 750, the indicator in the target copy structure 200 for the data block is updated to indicate that the data block has been copied. In a particular implementation of the invention, the indicator in the target copy structure 200 is set to zero.

  Thus, in a specific implementation of the present invention, incremental virtual copy operations are accomplished by monitoring writes (ie, updates) and recording changes to the tracks of the volumes that participate in the immediate virtual copy relationship. After the initial immediate virtual copy operation, tracks updated in either the source volume or the target volume can be copied from the source volume to the target volume without copying the entire source volume.

  Enterprise Storage Server, FlashCopy, and 3990 are trademarks of International Business Machines Corporation or common law trademarks in the United States and / or other countries.

Additional Implementation Details The described technique for incremental virtual copying is a standard programming to produce software, firmware, hardware, or any combination thereof, as a method, apparatus, or product, and It can be implemented using engineering techniques. As used herein, the term “product” refers to code or logic implemented in hardware logic (eg, an integrated circuit chip, programmable gate array (PGA), application specific integrated circuit (ASIC), etc.), or magnetic Computer readable media such as storage media (eg, hard disk drive, floppy disk, tape, etc.), optical storage (CDROM, optical disk, etc.), volatile and non-volatile memory devices (eg, EEPROM, ROM, PROM, RAM) , DRAM, SRAM, firmware, programmable logic, etc.). The code on the computer-readable medium may further be accessible through a transmission medium or from a file server on the network. In such a case, the product on which the code is implemented may include transmission media such as network transmission lines, wireless transmission media, signals propagating through the air, radio waves, infrared signals, and the like. Accordingly, the “product” may include a medium in which the code is embodied. Further, a “product” can include a combination of hardware and software components in which code is embodied, processed, and executed. Of course, one of ordinary skill in the art can make many modifications to this configuration without departing from the scope of the present invention, and the product can include any information supporting media known in the art. Will recognize.

  The logic of FIGS. 4-8 describes specific operations that occur in a specific order. In alternative implementations, certain logic operations may be performed in a different order, or modified or removed. Furthermore, operations can be added to the logic described above and still be compatible with the described implementation. Further, the operations described herein may occur sequentially, or certain operations may be processed in parallel, or operations described as being performed by a single process may be distributed. It may be executed by.

  The illustrated logic of FIGS. 4-8 can be implemented in software, hardware, programmable and non-programmable gate array logic, or any combination of hardware, software, or gate array logic.

  FIG. 9 illustrates the architecture of a computer system that can be used in accordance with a particular implementation of the present invention. Storage controller 100 and / or host 140 may implement computer architecture 800. The computer architecture 800 includes a processor 802 (eg, a microprocessor), memory 804 (eg, volatile memory device), and storage 810 (eg, magnetic disk drive, optical disk drive, optical disk drive, tape drive). Etc.) can be implemented. An operating system 805 can execute in the memory 804. The storage 810 can also include a self-contained storage device, or a mounted storage or a network accessible storage. The computer program 806 in the storage unit 810 can be read into the memory 804 and executed by the processor 802 by methods known in the art. The architecture further includes a network card 808 that enables communication with the network. An input device 812 is used to provide user input to the processor 802, which is known to the keyboard, mouse, pen stylus, microphone, touch sensitive display screen, or any other art. An actuation or input mechanism can be included. The output device 814 can render information transmitted from the processor 802 or other components such as a display monitor, printer, storage, and the like. The computer system's computer architecture 800 may include fewer components than those shown, may include additional components not shown here, or may include some combination of the components shown and additional components. But you can.

  Computer architecture 800 is known in the art such as mainframes, servers, personal computers, workstations, laptops, handheld computers, telephony devices, network appliances, virtualization devices, storage controllers, etc. Any computing device can be included. Any processor 802 and operating system 805 known in the art can be used.

  The above description of implementation of the invention has been given for the purposes of illustration and description. The above description of implementation of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto. The above specifications, examples, and data are sufficient to describe the manufacture and use of the composition of the invention. Since many implementations of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

FIG. 2 illustrates in a block diagram a computing environment in accordance with certain implementations of the invention. FIG. 2 illustrates in a block diagram a computing environment in accordance with certain implementations of the invention. Fig. 4 illustrates various structures according to certain implementations of the invention. Fig. 4 illustrates logic for updating a structure in accordance with a particular implementation of the present invention. Fig. 4 illustrates logic for performing an incremental virtual copy operation in accordance with a specific implementation of the present invention. Fig. 4 illustrates logic implemented in a write process for processing a write operation in accordance with a particular implementation of the present invention. Fig. 4 illustrates logic implemented in a read process for processing a read operation in accordance with a particular implementation of the present invention. Fig. 4 illustrates a background copy process according to a specific implementation of the present invention. Fig. 2 illustrates a computer system architecture that may be used in accordance with certain implementations of the invention.

Claims (9)

In a system for transferring data between a source storage and a target storage, a method for reducing the amount of data transferred,
The system
One or more host computers;
One or more storage controllers connected to the host computer via a network;
A source storage that may be connected to the storage controller, the source storage including one or more source data blocks as a source volume;
A target storage that can be connected to the storage controller, comprising one or more target data blocks as a target volume, the target data blocks being all or part of the source volume Maintaining a copy of the target storage and
Including
The storage controller receives an input or output request to the source storage unit or the target storage unit from the host computer, directs the request to the source storage unit or the target storage unit, and further, the source storage unit and the target storage unit Control data transfer to and from the target store,
The storage controller
System memory,
A source cache that can be connected to the source storage, wherein the data update is maintained in the source storage until data is written to the source storage;
A target cache that can be connected to the target storage, wherein the target cache maintains data updates until data is written to the target storage; and
With non-volatile cache
Including
The storage controller
A read process for reading data from the source store to the source cache and from the target store to the target cache;
A write process for writing data from the source cache to the source storage and from the target cache to the target storage;
A virtual copy process that transfers data from the source storage to the target storage and performs a virtual copy operation;
Can be loaded into the system memory and executed,
The non-volatile cache is
A source change record structure; and
A target change recording structure;
With the target copy structure
Remember
The source change recording structure includes a first indicator for each source data block, the first indicator being last transferred to the target store as a virtual copy operation . since when, indicates whether the source data block has been updated,
The target change recording structure includes a second indicator for each target data block, the second indicator corresponding to the target data block as a virtual copy operation by the target data block . since when it is updated by the source data block, it indicates whether or not the target data block has been updated,
The target copy structure includes a third indicator for each target data block, the third indicator transferring a source data block to the target data block as a virtual copy operation. Whether it should be
The method provides the system with a virtual copy operation.
Between one or more source volumes of the source store and a target volume of one or more target stores corresponding to the one or more source volumes of the target store Establishing a virtual copy relevance;
The third indicator to indicate that a source data block is to be retrieved from the source store and that the source data block is to be copied from the source store to the target store A step of updating
Updating the first indicator to indicate that the source data block has not been updated since the last time the source data block was transferred to the target store as a virtual copy operation;
Since the last transferred to target storage unit as the virtual copy operation, comprising and a step of updating the second indicator to indicate that the target data block has not been updated, Said method. The method includes:
Receiving a write request to a data block;
Determining whether the data block to be written is within the virtual copy association;
Determining if the data block to be written is in the target storage if it is in the virtual copy relevance;
Updating the second indicator when the data block to be written is in the target store;
Updating the first indicator if the data block to be written is not in the target store;
Performing a write to the data block;
The method according to claim 1, further comprising: The method includes:
Receiving a read request for a data block;
Determining whether the data block to be read is within the virtual copy association;
Determining if the third indicator indicates that the read target should be the source store when in the virtual copy relevance;
Reading a block of data from the source store if the third indicator indicates that the read target should be the source store;
Reading a data block from the target store if the third indicator does not indicate that the read target should be the source store;
The method according to claim 1, further comprising: The method includes:
If you decide to copy the data block in the background,
If the third indicator indicates that the data block has not been copied, the data block is read, copied to the target store, and the data block is copied to indicate that the data block has been copied. Updating the third indicator;
Processing the next data block if there is a next data block to be processed if the third indicator indicates that the data block has been copied;
The method according to claim 1, further comprising: A system for transferring data between a source store and a target store,
One or more host computers;
One or more storage controllers connected to the host computer via a network;
A source storage that may be connected to the storage controller, the source storage including one or more source data blocks as a source volume;
A target storage that can be connected to the storage controller, comprising one or more target data blocks as a target volume, the target data blocks being all or part of the source volume Maintaining a copy of the target storage and
Including
The storage controller receives an input or output request to the source storage unit or the target storage unit from the host computer, directs the request to the source storage unit or the target storage unit, and further, the source storage unit and the target storage unit Control data transfer to and from the target store,
The storage controller
System memory,
A source cache that can be connected to the source storage, wherein the data update is maintained in the source storage until data is written to the source storage;
A target cache that can be connected to the target storage, wherein the target cache maintains data updates until data is written to the target storage; and
With non-volatile cache
Including
The storage controller
A read process for reading data from the source store to the source cache and from the target store to the target cache;
A write process for writing data from the source cache to the source storage and from the target cache to the target storage;
A virtual copy process that transfers data from the source storage to the target storage and performs a virtual copy operation;
Can be loaded into the system memory and executed,
The non-volatile cache is
A source change record structure; and
A target change recording structure;
With the target copy structure
Remember
The source change recording structure includes a first indicator for each source data block, the first indicator being last transferred to the target store as a virtual copy operation . since when, indicates whether the source data block has been updated,
The target change recording structure includes a second indicator for each target data block, the second indicator corresponding to the target data block as a virtual copy operation by the target data block . since when it is updated by the source data block, it indicates whether or not the target data block has been updated,
The target copy structure includes a third indicator for each target data block, the third indicator transferring a source data block to the target data block as a virtual copy operation. Whether it should be
In order to enable the virtual copy operation, the system
Virtual copy between one or more source volumes of the source storage and target volumes of one or more target storages corresponding to the one or more source volumes of the target storage Establish relevance,
The third indicator to indicate that a source data block is to be retrieved from the source store and that the source data block is to be copied from the source store to the target store Update
Updating the first indicator to indicate that the source data block has not been updated since the last time the source data block was transferred to the target store as a virtual copy operation;
Updating the second indicator to indicate that the target data block has not been updated since it was last transferred to the target store as the virtual copy operation;
Said system. Receive a write request to a data block,
Determining whether the data block to be written is within the virtual copy association;
If it is in the virtual copy relationship, determine whether the data block to be written is in the target storage;
Updating the second indicator when the data block to be written is in the target store;
Updating the first indicator if the data block to be written is not in the target store;
Performing a write to the data block;
The system according to claim 5. Receive a read request to the data block,
Determining whether the data block to be read is within the virtual copy association;
If in the virtual copy relevance, determine whether the third indicator indicates that the read target should be the source store;
Read a data block from the source store when the third indicator indicates that the read target should be the source store
Reads a block of data from the target store if the third indicator does not indicate that the read target should be the source store;
The system according to claim 5. If it is determined that the data block is copied in the background,
If the third indicator indicates that the data block has not been copied, the data block is read, copied to the target store, and the data block is copied to indicate that the data block has been copied. Update the third indicator,
If there is a next data block to be processed when the third indicator indicates that the data block has been copied, process the next data block;
The system according to claim 5. The computer program which makes a computer system perform each step of the method of any one of Claims 1-4 .

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